LABORATOIRE DE PHYSIQUE THEORIQUE DE LA MATIERE CONDENSEE

We present models where γ+ and γ−, the exponents of the susceptibility in the high- and low-temperature phases, are generically different. In these models, continuous symmetries are explicitly broken down by discrete anisotropies that are irrelevant in the renormalization-group sense. The Zq-invariant models are the simplest examples for two-component order parameters (N=2) and the model with icosahedral symmetry for N=3. We accurately compute γ+−γ− as well as the ratio ν/ν′ of the exponents of the two correlation lengths present for T<Tc.http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.200601